Lu2O3-doped ZnO-Bi2O3-based varistor ceramics samples were prepared by a conventional mixed oxide route and sintered at temperatures in the range of 900-1 000°C,and the microstructures of the varistor ceramics sa...Lu2O3-doped ZnO-Bi2O3-based varistor ceramics samples were prepared by a conventional mixed oxide route and sintered at temperatures in the range of 900-1 000°C,and the microstructures of the varistor ceramics samples were characterized by X-ray diffractometry(XRD)and scanning electron microscopy(SEM);at the same time,the electrical properties and V-I characteristics of the varistor ceramics samples were investigated by a DC parameter instrument for varistors.The results show that the ZnO-Bi2O3-based varistor ceramics with 0.3%Lu2O3(molar fraction)sintered at 950°C exhibit comparatively ideal comprehensive electrical properties.The XRD analysis of the samples shows the presence of ZnO,Bi-rich,spinel Zn7Sb2O12 and Lu2O3-based phases.展开更多
Varistor ceramics of ZnO Bi 2O 3 TiO 2 Sb 2O 3 system have been fabricated by introducing pre fabricated ZnO seed grains with different size distributions respectively. The results show that the varistor properties we...Varistor ceramics of ZnO Bi 2O 3 TiO 2 Sb 2O 3 system have been fabricated by introducing pre fabricated ZnO seed grains with different size distributions respectively. The results show that the varistor properties were significantly influenced by the size of introduced seed grains, and introducing larger seed grains is more advantageous to the modification of microstructure and the improvement of varistor properties. The varistor properties were considerably improved with a moderately increased sintering temperature or time, whereas degraded apparently when the sintering temperature or time was excessively increased. Compared with the sintering time, the sintering temperature plays a more critical role in determining the varistor properties. By introducing pre fabricated ZnO seed grains into the original powders, low voltage ZnO varistor ceramics possessing the desired electrical properties have been produced with a sintering temperature of about 1 210 ℃ and a sintering temperature of 2～2.5 h. [展开更多
The effect of Mn_(3)O_(4)addition on microhardness,microstructure and electrical properties of vanadium oxide doped zinc oxide varistor ceramics is systematically investigated.The Vicker’s microhardness HV has decrea...The effect of Mn_(3)O_(4)addition on microhardness,microstructure and electrical properties of vanadium oxide doped zinc oxide varistor ceramics is systematically investigated.The Vicker’s microhardness HV has decreased with increasing the amount of Mn3O4.Also,the average grain size has decreased from 27.51μm to 19.55μm with increasing the amount of Mn_(3)O_(4) up to 0.50 mol%,whereas an increase in Mn_(3)O_(4) up to 0.75 mol%has caused the average grain size to increase and then it decreases with increasing Mn_(3)O_(4)from 0.75 mol%to 1.00 mol%.The sintered density has decreased from 5.38 g/cm3 to 5.31 g/cm3 with increasing the amount of Mn_(3)O_(4).The varistor ceramic modified with 0.50 mol%Mn_(3)O_(4) has exhibited excellent nonlinear properties,with 16.29 for the nonlinear coefficient and 441.9μA/cm2 for the leakage current density.Furthermore,the sample doped with 0.50 mol%Mn_(3)O_(4) has been found to possess donor density as 0.77×10^(18) cm^(-3) and 0.916 eV barrier height.展开更多
基金Project(50902061)supported by the National Natural Science Foundation of ChinaProject(2011-22)supported by the State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University,China+3 种基金Project(20100471380)supported by the China Postdoctoral Science FoundationProject(J50102)supported by the Leading Academic Discipline Program of Shanghai Municipal Education Commission,ChinaProject(10KJD430002)supported by the Universities Natural Science Research Program of Jiangsu Province,ChinaProject(2010002)supported by the Jiangsu University Undergraduate Practice-Innovation Training Program,China
文摘Lu2O3-doped ZnO-Bi2O3-based varistor ceramics samples were prepared by a conventional mixed oxide route and sintered at temperatures in the range of 900-1 000°C,and the microstructures of the varistor ceramics samples were characterized by X-ray diffractometry(XRD)and scanning electron microscopy(SEM);at the same time,the electrical properties and V-I characteristics of the varistor ceramics samples were investigated by a DC parameter instrument for varistors.The results show that the ZnO-Bi2O3-based varistor ceramics with 0.3%Lu2O3(molar fraction)sintered at 950°C exhibit comparatively ideal comprehensive electrical properties.The XRD analysis of the samples shows the presence of ZnO,Bi-rich,spinel Zn7Sb2O12 and Lu2O3-based phases.
文摘Varistor ceramics of ZnO Bi 2O 3 TiO 2 Sb 2O 3 system have been fabricated by introducing pre fabricated ZnO seed grains with different size distributions respectively. The results show that the varistor properties were significantly influenced by the size of introduced seed grains, and introducing larger seed grains is more advantageous to the modification of microstructure and the improvement of varistor properties. The varistor properties were considerably improved with a moderately increased sintering temperature or time, whereas degraded apparently when the sintering temperature or time was excessively increased. Compared with the sintering time, the sintering temperature plays a more critical role in determining the varistor properties. By introducing pre fabricated ZnO seed grains into the original powders, low voltage ZnO varistor ceramics possessing the desired electrical properties have been produced with a sintering temperature of about 1 210 ℃ and a sintering temperature of 2～2.5 h. [
文摘The effect of Mn_(3)O_(4)addition on microhardness,microstructure and electrical properties of vanadium oxide doped zinc oxide varistor ceramics is systematically investigated.The Vicker’s microhardness HV has decreased with increasing the amount of Mn3O4.Also,the average grain size has decreased from 27.51μm to 19.55μm with increasing the amount of Mn_(3)O_(4) up to 0.50 mol%,whereas an increase in Mn_(3)O_(4) up to 0.75 mol%has caused the average grain size to increase and then it decreases with increasing Mn_(3)O_(4)from 0.75 mol%to 1.00 mol%.The sintered density has decreased from 5.38 g/cm3 to 5.31 g/cm3 with increasing the amount of Mn_(3)O_(4).The varistor ceramic modified with 0.50 mol%Mn_(3)O_(4) has exhibited excellent nonlinear properties,with 16.29 for the nonlinear coefficient and 441.9μA/cm2 for the leakage current density.Furthermore,the sample doped with 0.50 mol%Mn_(3)O_(4) has been found to possess donor density as 0.77×10^(18) cm^(-3) and 0.916 eV barrier height.
